Tower



July 21, 1942. N. aloBBARD TOWER Filed March 4, 1941 3 Sheets-Sheet 1 P m% Si@ 1 [wem/07. /VOEMAW 5. 0554,90,

July 21, 1.942. N. B. OBBARD TOWER Filed March 4, 1941 S Sheets-Sheet 2 [Q7/vena?? /l/o/m/v 5. 0554/90 692ML; f i/ ifo/wey.

July 21, 1942. N. a'. OBBARD TOWER Filed March 4, 1941 3 Sheets-Sheet 3 v W@ 5 M5 6.

mwg. [4 M W Patente'd July 21, 1942 STATES `3 Claims.

The present invention relates to improvements in towers well suited for use as an oil well derrick or as a support for water tanks, transmission lines or similar overhead loads. Heretofore such towers were commonly constructed with legs to take the vertical loads and bracing which, in combination with legs, take the transverse, torsional and other loads. In towers of this general character heretofore used, the bracing has not been designedly intended to, nor is it suitable to, eiectively resist vertical loads Vto any material or signicant extent.

Maximum vertical loads due to the formation of ice, temporary overloads or the like do not ordinarily occur simultaneously with maximum transverse and torsional loads which are generally imposed by wind storms and the like.

The chief object of the present invention is 'to provide a tower with a bracing system incorporated therein which' will assist very materially :in carrying vertical loads. Another object `is to provide a tower in which the leg system and the bracing system are each individually capable of taking a substantial share-of the vertical loads imposed on the structure. A further object is to provide 4a tower so constructed and arranged that the bracing system alone is of Vsuch character that it can sustain the vertical .load normally imposed on the tower quite independently of the leg system of the tower.

Th'e above and further features y01 the invention will be fully apparent from a consider-ation of the following detailed disclosure, the accomp'anying drawings and the appended claims.

In the accompanying drawings;

Figure 1 is a perspective view of a tower-embodying the invention, the members of the leg system and the bracing system respectively being shown in single lines in the interest `of simplicity of illustration;

Figure 2 is a perspective View of the bracing system of Figure 1 minus the leg system;

Figure 3 is a perspective view of the :leg system of Figure 1 minus the bracing system shown in Figure 2;

Figure 4 is an enlarged perspective view of the upper and lower portions of the tower of the present invention illustrating suitable structural members for use in the leg system and bracing system;

Figure 5 is 4a view somewhat similar to Figure 4 showing an alternative arrangement of the structural members constituting the leg system and the bracing system; and

Figure 6 shows leg sections.

Referring rst to the embodiment of the invention diagrammatically lshown in Figures 1 to 3 of the drawings, the numerals I, 2, 3 and 4 represent the main structural members or legs of a leg system which, as viewed in plan, are :located substantially for approximately on the points yof a rectangle, although vit is to be understood that a tower embodying 'the teachings of the present invention may be vtriangular or any other suitable polygonal form. For convenience of illustration, 4a tower substantially square in plan has been shown. Thus the legs I, 2 3 and 4 lie along .lines comparable to' the edges loi the frustum of a pyramid having a square base.

The bracing system suchas shown inthe skeleton view of Figuret?. vincludes a .plurality of substantially horizontally disposed panel sections 5, 5, 1, 8 and 9. The number Yof these panel sections will, of course, vary in towers of diierent heights and the number may varyin accordance with the load to be imposed on the tower. 'The panelsare preferably parallel.

The bracing system includes members interconnecting the different panel sectionsand at the bottom of the tower there are suitable bracing elements connecting the b-ase with the first panel section 5. The actual design and .arrangement of the elements constituting the bracing system may be Varied Vto suit various load conditions. For purpose of illustration, but not limitation, I have shown, for example in Figures 1 and 2, a bracing system in which upwardly diverging elements I0 and Il at each side of the tower meet at f|2 at a Vplane intermediate the base land the first panel section 5 and then continue in the form of extensions IDa and Ha to the corner points 5C of the panel member `5. Thus the bracing system illustrated takes the form on each side of the tower of a bottom inverted V on which is superposed a top V, the legs of the bottom V comprising the members Il! and Il and the legs of the top V comprising members ma and lla, the apexes of said top and bottom Vs meeting at the points as indicated at l2. The points or apexes of the several Vs lie in aplane which is intermediate the adjacent panel sections 'as shown.

The bracing system between the panels '5 and 6 is quite similar to that between the base .and the panel 5. For example, there is a bottom inverted V comprising members 2!! and 2l Awhich meet at the point 22. 'Each member 20 is extended as indicated at 2li, and similarly each member 2| is extended as indicated at Zia. The members 20a and Zia vjoin the panel 6 at the corners 6C. In like manner, between the panels 6 and 'l there are leg elements 3H, 3|, 3l!a and 31a, the latter of which join the panel member 'l at the corners lc. Similarly disposed members 40 and 4l, 49a and dla join the panel member 8 at the corners 8. In like manner the members U, 5I, 5l!a and Sia, which constitute the bracing elements between the panel 8 and the topmost panel member 9, are joined thereto at the corners 9. The proportions of vertical load carried by the leg system l, 2, 3 and 4 (shown detached in Figure 3) and the bracing system (shown detached in Figure 2) may be predetermined by their respective relative stiifness or by balance beams at the top or by other equivalent systems.

In Figure 4 I have illustrated certain physical members which may be employed to provide for a division of the vertical load between the leg and bracing systems. are permanently anchored to a suitable foundation slab F by means of suitable connecting anchors f. A slidable joint is provided between the bracing system and the leg system. For eX- ample, as illustrated in detail, the angle member 8a constituting one of the elements of the panel 8 is connected with a corner angle element Gb which makes a sliding engagement with the adjacent leg member. One suitable way of providing such a slidable connection is to employ bolts which make a fairly snug t with holes in the angle member 8b and pass freely through elongated slots s formed in the leg members. Thus the leg system can partake of limited movement independent of the bracing system.

As here illustrated, the legs A proper distribution of the load between the leg system and the bracing system is made by a balance beam B at the top, as best shown in Figure 4.-. The vertical loads may be assumed to be concentrated at the top as indicated by the heavy arrows LB and to react on the balance pin bearing Bp. 'I'he beams B will transmit their loads to the leg system through the pin bearings 60. The angle members, such as shown at 8b (Figure 4), are slidably secured to the leg system by the pin and slot connection, as shown. Loads are transmitted from the balance beam B to the bracing system through the pin bearing connection 62. Thus it is apparent that the vertical overhead load is distributed in such manner that a predetermined proportion thereof is taken respectively by the leg system and the bracing system.

Various loads may be provided for. For example, considering the moment arms and y in Figure 4, the proportion of x/y to give the desired loa-d distribution between legs and bracing may be such that any predetermined fraction of the load may be taken respectively by either the leg system or the bracing system. It will be understood that the load is applied to the beams B at the points indicated by the arrows LB (Figure 4) situated between the leg and the bracing bearing points to give the required ratios of loading. The upward reaction of the leg system is indicated by the arrows UL. The upward reaction of the bracing system is indicated by the arrows UB.

Another arrangement for distribution of the vertical load between the leg and bracing systems is illustrated in Figure 5. In this embodiment of the invention the leg and bracing systems are connected together at each panel point, that is, to the several points where the panel frames 5, 6, 1, 8 and 8 intersect the legs at which planes the component elements of the bracing system are integrally connected to the leg system. As thus arranged the leg and bracing systems carry respective vertical loads in proportion to their stiffness under Vertical loa-ding. The relative stiffness of each is predetermined by selecting members oi the correct cross sectional area or, alternatively, by using different materials or different grades of steel in the two systems or, alternatively, by deforming some of the members to change their properties under load, or by applying initial tensions or compressions to certain of the members. The leg angles can be bent or reinforced to increase their column properties as shown in Figure 6.

The present invention contemplates systems in which the bracing is stable independently of the tower and the legs themselves may be employed as connecting members for the bracing at the panel points, as illustrated in Figure 5. However, it is within the spirit and scope of the invention to omit parts of the legs between the panel points without affecting the stability of the bracing system. In some places it is contemplated that the legs may be entirely dispensed with, in which case the complete tower would correspond to the form illustrated in Figure 2. Instead of omitting the legs entirely, it is contemplated that legs of much lighter weight than those ordinarily employed may be utilized resulting in the same total overall weight of the tower. This would require a relatively heavier bracing system but the nished tower having such heavy bracing will be peculiarly well adapted to resist the vibrational loads which occur during drilling wells and such loads as are imposed on the structure by gusts of wind and like stresses.

The invention has been illustrated and described in connection with a rectangular or square tower to facilitate and simplify illustration. However, the principles of the invention are equally applicable to triangular, pentagonal, hexagonal or other polygonal plan outlines as will be readily understood. It is also manifest that the principles of the invention may be equally well applied to a part of the tower, and it is contemplated that the legs may be used in conjunction with a bracing system only at such times when the tower is under heavy loads, as in well drilling work, and removed for later operating conditions when the loads are relatively much lighter. In such cases the legs or leg system would be used merely as temporary reinforcements, as will be understood. As hereinbefore suggested, in some cases the legs may be entirely eliminated for light structures, in which case the tower would be of the form shown in Figure 2 wherein all members are active in resisting vertical, transverse, torsional as well as other loads, including combinations of the aforesaid loads.

While I have shown and described quite precisely certain specific embodiments of the invention, it is to be understood that various modifications and rearrangements of the component parts of the structure may be made by those skilled in the art without departure from the invention as set forth in the appended claims.

I claim:

1. A tower of the character described comprising a leg system and a vertical load carrying bracing system slidably connected with the leg system, and an overhead load carrying structure including a beam, one end of which reacts on the leg system and the other end of which reacts on the bracing system.

2. A toWer of the character described comprisprising a bracing system which is itself stable ing a bracing system which is itself stable comcombined with a leg system, the bracing system bined With a leg system, the bracing system being being slidably connected with the leg system, slidably connected with the leg system, and supand a balance beam connected with both the porting means and connections for proportion- 5 leg and the bracing system for proportioning the ing the vertical load carried by each said system. vertical loads carried by each.

3. A tower of the character described com- NORMAN B. OBBARD. 

